Thebmometeb tube and method of making the same



Reissued June is, 1931 UNITED STATES PAATENT OFFICE m n iuoELLEn, or NEW YORK, N. Y.,

ASSIGNOR, BY MESN'E ASSIGNMENTQ TO MOELLEB INSTRUMENT COMPANY, INC.-, OF BROOKLYN, NEW YORK, A CORPORATION 01' NEW YORK TIB'ERIOMETER TUBE AND METHOD OF MAKING THE SAME Original N0. 1,753,801, dated April 8, 1930, Serial mi. 290,565, filed July 5, 1928. Application for reissue filed December 22, 1980. Serial No. 504,187.

The improvements relate to tubes for thermometers and the like and methods of making the same and have for their primary ob- 'ect the provision of a thermometer tube having effective means for rendering the mercury or other expansible fluid in the bore more clearly visible and more easily read in .connection with the usual scale or other temculty, however, has been encountered in so positioning and proportioning the backing that it will register properly with the I bore of the stem and the fluid therein throughout their length without making the said backing of such proportions that it will interfere with the background behind itsuch as the light shield at the back of the stemand thus lead to obscuration and confusion.

The present improvements ma dispense with the background or light shield at the back of the stem and employ a non-transparent, and preferably reflective film or, layer extending from the bore on either side to the periphery of the stem, or approximately thereto, throughout its reading length, lea-ving the bore clear, and a suitable colored backing behind said bore is then placed and made of any width necessary to provide a proper contrast for observation of the bore and the fluid column therein from any point of view at the front of the thermometer. The improvements also provide simple and eflicient means for making such a stem.

the said backing in the drawing process The stem provided by the present improvements is also believed to make reading of the thermometer more easy and accurate than the other stems with backing even when perfectly made.

In order to illustrate the present improvements the accoinpanyin drawings are provided and referred to erein. In the said drawings, Fig. 1 is an end view of a mold, with a block or blank formed in accordance with the'present improvements and before drawing cast therein, with the top or end cover removed to expose the end of said block;

Fig. 2 is a plan of the lower half or section of the mold with the backing and non-transparent layer molded therein, as indicated by the line 2 2 and the arrow in Fig. 1, the mold in this and the first figure being shown diagrammatically for the purpose of illustrat- Figs. 4 and 5 are transverse sections of modified forms of the stem made in accordance with the present improvements.

In making the thermometer stem and according to the method of the present improvements a mold in two parts, 1 and 2,

hinged together at one side as indicated at 3 and having complemental cavitiesl and 2", is preferably employed, each cavity being substantially semi-cylindrical in form and of sufficient size and length to mold a proper block or blank of glass. A removable metallic rod is also provided for the purpose of forming the bore in the molded block.

This mold is first opened and the cavities of both sections filled with glass in a heated,

plastic state, the one cavity, preferably the lower one, being filled with colored glass and y the upper one with uncolored, transparent glass. The plastic glass is then pressed, if necessary, in any suitable manner, and by any suitable means, such as are commonly used in glass molding establishments, and the rod 5 of iron orother material having a higher heat resistance than the glass and considerably longer than the mold cavity then placed on the mold section containing colored glass and pressed into the glass therein,suitable registering grooves beingprovided in the mold for the reception of the said'rod. The cavity containing the colored lam is not quite filled, and a film or layer 0 non-transparent glass, such as the ordinary white or opal glass, in a plastic state, is spread over the upper surface of the glass in the cavity to form a stratum of this glass onthe top surface This" layer of non-transparent lass should extend to about the middle or orizontal diameter of the rod. The mold is thenclosed and the two sections of the block permitted to unite to form a'complete cylindrical block with bore therein corresponding to the rod. In these operations, as in the re mainder of the operation, the heat of the mold rod and mold is maintained at a suflicient degree of temperature to insure that the glass is plastic throughout. The mold section cavities may also be filled slightly more than necessary to make the cylindrical block, so that when the mold is closed the glass therein will be under, compression.

The colored glass referred to is indicated at 6, the uncolored glass at 7 the stratum of non-transparent glass at 8 and the bore formedby the rod at 9. Instead of filling one-half of the mold with colored glass, it may be only partly filled, so as to provide abacking of the necessary width, or the bottom of the mold throughout all or part of its arch may have a layer or coating of colored and/or other non-transparent glass, as indicated at 10 in Fig. 4. Instead of this, a stem in accordance with the improvements may be made by molding the block entirely of uncolored glass, with the non-transparent diameteric layer and then coatin the outside of it on one side with colore glass as indicated at 11 in Fig. 5, as by dipping the block in a horizontal position in a vessel containing molten colored glass.

After the described steps have beenperformed the cover 12 of the mold is removed, the rod 5 also removed and the head of a blow ipe, such as that indicated at 13 in Fig- 3, wit plastic glass, as indicated at 14 thereon, applied to the end of the block. Preferably the rod is first removed and the two sections of the molded block permitted to unite while still hot and soft before opening the mold. The mold is stood on end when the top or cover is removed. Air pressure is maintained on the bore of the'glass in the mold by means of the blow pipe while the block is drawn to the desired length to form a suitable stem, the block adhering to the surface of the blow pi head during this operation, which is preceg d by removal of the mold.

During the drawing operation the body of the glass may be drawn out to any desired extent within wide limits by dipping the glass 'in a pot of molten glass to increase its volume. This dipping will of course add a layer of transparent glass on the outside of the origadded layer will be intercepted by the said non-transparent stratum or film, at the middle and the back of the stem. It will be apparent also that a block or blank of glass two inches in diameter can be drawn out to make a stem one-eighth inch in diameter more than one hundred times its length. The drawing operation in the present case does not differ essentially from similar operations well known and long racticed by those skilled in the art., It will be apparent, however, from the foregoing references to the operations performed and conditions encountered that the tube as originally molded becomes greatly attenuated and that the bore and backin go through the same transformation. The ore can be kept open if necessary by means of the gas pressure from the blow pipe, and the thermometer stem can be maintained at a constant thickness and symmetrically formed by means of suitable guages and forming devices used for that purpose. During this operation the stem may also be given a magnifying edge by pressing it and working it in a V-shaped mold or form. Where, however,

there is a narrow backing member between the bore and the back of the stem it is not possible to control it during the drawing operation so as to prevent it attimes from twisting moving from its proper position or becoming unduly attenuated so as to render it ineffective for that purpose.

The method or process herein described, as well as the stem itself may be varied withincertain limits without departing from the scope of the invention, so long as the essentials are retained. Various additions may also be made thereto.- For instance, in the dipping and drawing process the non-transparent layer may be widened by adding more of the non-transparent glass at the edges of the layer, and it will not affect the character or function of this layer if these additionsor the original depositspread toward the front or back of the thermometer to a certain ex.- tent. Neither is it necessary that the said layer shall be diametric, so long as it is sulficient to provide a non-transparent field extending on both sides of the bore-a sufiicient distance to shut out the colored backg'round from the eye focused on the bore and column of fluid therein. The molding of the blank or core before. drawing it, with or without dipping it in molten glass to add thereto is however believedto bean essential of the process and to be novel in this art.

The improvements herein described are not I limited in their application .to the form of stem illustrated but may be employed in the of the molded sections may be larger than the other, so as to produce a stem having an elliptical cross section, with the bore 9 and diaphragm 8 toward one end of the ellipse, so that the glass between them and the front will produce a magnifying effect even to the extent of causing the fluid column as thus magnified to apparently extend substantially from side to side of the stem and produce the Y visual effect of a column of approximately or exactly the same width as the stem. One of the sections may also be molded so as to produce the tapering magnifying edge, commonly used in clinical and other thermometers. It is also contemplated that the nontransparent layer or stratum may not only extend to the side edges of the stem but may extend beyond them and around the back of the stem, after the manner of the non-trans parent backing now commonly used, thus completely shutting out reflections from the colored backing except through the bore. Various. other uses of the improvements and modifications of the form illustrated will occur to those skilled in the art.

What I claim is:

1. A glass stem for thermometers or the like comprising a glass rod having a bore in the interior thereof and a non-transparent element therein extending from said bore toward the sides thereof. I

2. A glass stem for thermometers or the like comprising a glass rod having a bore in the interior thereof and a non-transparent element therein extending from said bore to the sides thereof. v

3. A glass stem for thermometers or the like-comprising a glass rod having a bore in the interior thereof and a non-transparent element therein extending from said bore to- Igvard the sides thereof on both sides of the ore.

4. A glass stem for thermometers or the like comprising a glass rod having a bore in the interior thereof and a non-transparent element therein extending from the side of said bore toward the sides thereof.

5. A glass stem forthermometers or the like comprising a glass rod having a bore in the interior thereofand a non-trans arent element therein extending from sai bore toward the sides thereof and a non-transparent backing member behind said nontransparent element arranged to direct light rays to the bore and ortions of the stem at the sides thereof, sai non-transparent element being arranged to intercept said rays at the sides of the bore. v

6. A glass stem for thermometers or th like comprising a glass rod having a bore in the interior thereof and a non-transparent element therein extending from said bore toward the sides thereof and a backing memward the sides thereof and a backin member of non-transparent material behin the said non-transparent element.

. 8. A glass stem for thermometers and the like comprising a glass rod having a central bore, a non-transparent element therein extending from the sides of the bore to the outer sides of the stem, but not'across the bore, and a backing member between the bore and the outer surface of the stem extending laterally beyond the bore and beyond the inner edges of the non-transparent element.

9. A glass stem for thermometers and the like comprising a glass rod havin a' central bore, a non-transparent. element therein extending from the sides of the bore to the outer sides of the stem butnot across the bore, a backing member between the bore and the outer surface of the stem extendinglaterally beyond the bore and beyond the inner edges of the non-transparent element and another backing member between the non-transparent element and the extreme outer surface of the stem and extending over the bore.

'10. A glass stem for thermometers and the like comprising a glass rod having a central bore, a non-transparent element therein exprlses moldin the stem in sections with an it interior bore or the reception of expansible fluid, uniting the two sections to form a continuous tube and embeddingtherein a strip v of non-transparent material extending laterally from the sides of the bore to the edges of the stem and also incorporating in the stem back of the bore a colored backing element. 1

12. The herein described method ofmaking .a lass stem for thermometers and the like w ich consists ofmolding the stem in sections with an inner longitudinal s ace adapted to form a bore for expansible uid,

incorporating in one of the sections a backing element extending laterally beyond said space, inserting between said sections nontransparent material extending from thebore space laterally and then uniting the said sections with the last named element between them, then drawing the blank thus formed to the desired length and thickness. 1 Y a 13. The herein described method of makinga glass stem or tube for thermometers and the like, which consists in placing glass in a plastic state in a mold having a greater diameter than the stem or tube to be produced, so as to form a segment of a stem block or blank, placing thereon a rod of material having a higher heat resistance than the glass to form a bore, molding another segment in manner similar to the first segmentand placin it on said first segment and the rod in a p astie state with the rod between the two segments, uniting the opposed surfaces of the segments to form a cylinder of glass with thick walls with the rod as a core, then removing the rod and drawing the block or blank thus formed to the desired length.

14. In the process as specified inv claim 13 inserting a film or layer of non-transparent material between the opposed surfaces of the segments before uniting them.

15. The herein described method of making a lass stem or tube for thermometers and the li e, which consists in' placing glass in a plastic state in a mold having a greater diameter than the'stem or tube to be produced, so as to form a segment of a stem block or blank, molding another segment in manner similar to the first segment and placing it on said first segment in a plastic state placing a bar of material having a higher heat resistance than the glass between the two segments, uniting the opposed surfaces of the segments to form a cylinder of glass with thick walls with the bar as a core, then removing the bar and drawing the block or blank thus formed to the desired length.

16. In the process as specified in claim 15 inserting a film or layer of non-transparent material between the opposed surfaces of the segments before uniting them.

17. A glass stem for thermometers or the like comprising a glass rod havinga bore in the interior thereof,-a non-transparent element therein extending from said boretoward the sides thereof, and a non-transparent element behind said bore extending laterally thereof and toward the plane of said bore.

18. The'method or rocess of .making a glass stem or tube for t ermometers and the like which consists in placing glass in a.

plastic state in a mold having a greater diameter than the stem or tube to be produced placing in fixed position relative to the final molded mass of glass in the interior of said mold and before completing the filling of said mold an attenuated member of material havin a relatively high heat resistance and extending through the mold cavity, embedding said member in the said glass in the like which consists in placing glass in a.-

plastic state in a mold having a greater di ameter than the stem ortube to be produced, placing in the interior of said mold and before completing the filling of said mold an attenuated member of material having a rela ti'velv high heat resistance, embedding said mem er in the said glass in the mold, and also embedding in said glass a strip of non-transparent material in position between said member and the outer surface of the glass, so as to form acylinder of glass in said mold with thick walls and with the said member as a core, then removing said member from the cylinder of glass, so as to leave a bore having substantially the size and shape of said member, then removing" the said glass cylinder from the mold, and then drawing it to the desired length.

20. The method of making glass tubes for thermometers and the like which consists in first moldinga thick block or blank with a here by filling a mold with plastic glass and embedding in said lass duringtheoperation of filling the mold%) inserting in said mold before filling a high heat resisting rod or bar of relatively small diameter and surrounding the same with lass after such insertion, then removing the bar, and then removing the block or blank thus formed and drawing it and the bore therein to the desired length and attenuation.

Witness my hand this 19th day of 'December, 1930, county of New York, State of New York.

MAX E. MOELLER. 

